Patent GB-1507459-A (GB)
Title: Disc-record players
IPC: G11B3/085
Filed: 1974-12-18
Abstract: 1507459 Record player PLESSEY CO Ltd 17 Dec 1975 [18 Dec 1974] 54817/75 Heading G5R In a disc record player, the control mechanism including the cam gear, drive pinion &c. are formed as a sub-assembly which can be mounted over a wide range of positions on the turntable support plate and coupled to pinion drive means by e.g. a drive belt and to operation control elements and levers by suitably dimensioned links. The movement of the cam gear is damped and the gear can be rotated in a direction opposite to its normal driven direction to raise the pick-up arm by operation of a cueing lever and restored to its initial position by spring means to lower the pick-up arm. The sub-assembly 10 is mounted between plates 11, 12 and includes cam gear 13 which is mounted, Fig. 7, not shown, such that its rotation is adjustably clamped by frictional interaction between support washers to which a viscous fluid is applied. The toothless portion of the gear extends over a wide angle than normal, e.g. 20 degrees to allow said movement during cueing and the gear is held in its rest or indexed position by a spigot 47 on the gear engaging in a V-shaped notch 49 in a lever 46. For manual operation a selector switch 32 with links 100, 101 and 33 is moved to manual position so that motor switch 35 is operated to drive the turntable at a selected speed and a control lever 34 is moved to its manual position. The pick-up arm can now be deposited on the record either manually or by operation of a cue lever 36 which via link 38 rotates a cam lever 37 clockwise so that cam surface 40 engages rib 41 on the cam gear and rotates it clockwise through a small angle, e.g. 20 degrees from the indexed position shown. As the cam moves a lifting blade 43 rides up ramp 50 on the cam gear and via lift pin raises the pick-up arm from its rest. Movement of the cam gear also pivots arm 48 against the action of spring 45 as the spigot 47 moves over cam surface 48. The pick-up arm is now moved manually to position the arm over a required record groove and the cue lever is restored to its initial position whereby the cam gear is returned to its indexed position by the action of cam 48 on the spigot 47. This return movement and thus the lowering of the pick-up arm being damped as described. After play of the record a lever 53 is rotated to move a trip lever 55 into the path of a striker 56 on pinion 29 which is driven by belt 30 from the turntable spindle. As a result the cam gear is moved into engagement with the pinion and driven counter clockwise for a complete revolution, the last part of which drive is by means of the cam 48 acting on spigot 47. During the revolution the pick-up arm is raised by cam 58 acting on lifter blade 43 and its lift pin, the arm is moved to its rest position by cam follower lever 59 moved by a pin 60 riding on a cam surface of the gear and finally the arm is lowered to its rest as the lifter blade moves down cam 50. Additionally a spring member (not shown) deflects control lever 34 so that selector switch 32 is released to the off position and the drive motor switched off. For automatic control switch 32 is moved to automatic position so that the motor is again energized and the control lever 34 now moved to its automatic position. Momentary operation of impulse switch 64 now acts via rod 67 and arm 65 to move trip lever 55 into engagement with the striker 56 so that the cam gear is driven. Thus the pick-up arm is lifted, a record release mechanism is operated via link 71 by cam follower lever 59 which also moves the pick-up arm to a position set by record size selector switch 72 which via rod 73 moves size selector arm 75 to a position where a pin 77 of the arm engages a step 79-81 depending on record size, finally the pick-up arm is lowered on to the record. At the end of record play the cam gear is again actuated to prepeat the automatic cycle. At the end of the first automatic cycle the control lever 34 is moved from its automatic position to a position intermediate that and the manual position and is retained in this intermediate position until the last record is detected when it is moved to the manual position in readiness for switch off when this last record has been played. Means are also provided for repeat operation.